Just to answer to Cabola's question. But for me, local upgrade to IPS 4 from 3.4.7 under localhost or localhost/myforum or 127.0.0.1 or 127.0.0.1/myforum don't work. Already explained to support. Upgrade checker want a valid license to continue to the next step.... The solution is to replace the controller which is called by the script itslef in the URL to bypass licensing step. (license to applications) So, upgrade / install will continue with no license. And Dashboard will inform you that you don't have license. Welcome in DRM century...
Most of the time, they don't have Client account. They have an unlicensed software and didn't know that they need a verified account to download files from IPS.
it is part of the profits to own a legal license.
As mentionned on IPS website, You can convert from other community software with http://www.invisionpower.com/convert In your case, you just need to buy a Invision Power Board license to upgrade your community, It's simple,
If you need help you can contact Invision Power Support to help you, upgrading your board.